UC San Diego Library – Scripps Digital Collection

Trout fishing has long dominated California's freshwater angling picture. In 1936 roughly half of the State's 300,000 angling licensees caught trout. In 1962, with 1,588,000 licensees, the proportion remained unchanged. Heavy angling pressure early depleted trout in many roadside waters. The stocking of "catchable-sized" hatchery trout soon followed, beginning in southern California before World War II. It spread rapidly throughout the State after the war, as the Wildlife Conservation Board provided more than $4 million for trout hatcheries. Currently, about seven million 7-to-8-inch rainbow trout (Salmo gairdnerii) are stocked annually in California, at a cost of $1,366,000 (Fiscal Year 1962–63). The 1956 distribution of fish is shown in Figure 1. The same general pattern continues. This program created a need for rapid, inexpensive survey methods to determine if the many new "catchable" fisheries were functioning satisfactorily. Accordingly, a research project, D-J F-14-R, "Evaluation of Catchable Trout Stocking," was set up in 1954 to develop such a method, and to evaluate the new program. In 1956, this project was incorporated into the broader "Trout Management Study," D-J F-8-R. This project answered many troublesome questions. It quickly developed the desired new survey methods (Butler, 1957; von Geldern, 1961) and used them to inventory a series of widely scattered fisheries in various types of lakes and streams (Jensen, 1958; Delisle, 1959; Jensen and Butler, 1959; Kabel and Butler, 1959; Kabel, 1960; von Geldern and Kabel, 1960; Weidlein, 1960). The results, summarized in this report, provide insight into the program as a whole.